U.S. patent number 8,057,359 [Application Number 12/211,963] was granted by the patent office on 2011-11-15 for twin clutch type speed change control system.
This patent grant is currently assigned to Honda Motor Co., Ltd.. Invention is credited to Hiroyuki Kojima, Yoshiaki Nedachi, Takashi Ozeki, Haruomi Sugita, Yoshiaki Tsukada.
United States Patent |
8,057,359 |
Tsukada , et al. |
November 15, 2011 |
Twin clutch type speed change control system
Abstract
A twin clutch type speed change control system changes over the
gear position by switching between a pair of clutches, to reduce
the collision sound generated between a free gear and a slide
member at the time of changeover of the gear position. In the twin
clutch type speed change control system designed to perform gear
position changeovers between odd-ordinal gear positions and
even-ordinal gear positions through a process in which an engaged
clutch is disengaged whereas a disengaged clutch is engaged, the
formerly disengaged clutch is supplied with a minute oil pressure
P1 toward the clutch engaging side and is thereby preliminarily
moved by a minute amount toward the clutch engaging side, at the
time of changeover of the gear position.
Inventors: |
Tsukada; Yoshiaki (Saitama,
JP), Ozeki; Takashi (Saitama, JP), Kojima;
Hiroyuki (Saitama, JP), Nedachi; Yoshiaki
(Saitama, JP), Sugita; Haruomi (Saitama,
JP) |
Assignee: |
Honda Motor Co., Ltd. (Tokyo,
JP)
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Family
ID: |
39790103 |
Appl.
No.: |
12/211,963 |
Filed: |
September 17, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090078072 A1 |
Mar 26, 2009 |
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Foreign Application Priority Data
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Sep 26, 2007 [JP] |
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2007-249813 |
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Current U.S.
Class: |
477/180; 477/79;
74/335 |
Current CPC
Class: |
F16D
48/066 (20130101); F16H 61/688 (20130101); F16D
25/10 (20130101); F16D 11/10 (20130101); F16D
21/06 (20130101); F16D 2500/50684 (20130101); F16H
2306/18 (20130101); F16D 2500/70406 (20130101); F16H
2061/062 (20130101); F16H 3/16 (20130101); F16H
3/006 (20130101); F16D 2021/0692 (20130101); F16D
2011/008 (20130101); F16D 2500/70282 (20130101); F16D
2500/1086 (20130101); Y10T 74/19251 (20150115); F16D
2021/0661 (20130101) |
Current International
Class: |
B60W
10/02 (20060101); B60W 10/00 (20060101); F16H
59/00 (20060101) |
Field of
Search: |
;477/166,174,175,176,180,79,143 ;74/329,330,331,335,340 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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19751456 |
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May 1999 |
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DE |
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102006006207 |
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Sep 2006 |
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DE |
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0315596 |
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May 1989 |
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EP |
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1617110 |
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Jan 2006 |
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EP |
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1803956 |
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Jul 2007 |
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EP |
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2003-39960 |
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Feb 2003 |
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JP |
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2007-177904 |
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Jul 2007 |
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JP |
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Other References
English translation of DE19751456A1, May 19, 2011,
http://translationgateway.epo.org. cited by examiner.
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Primary Examiner: Pang; Roger
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Claims
What is claimed is:
1. A twin clutch type speed change control system comprising: a
transmission mechanism having a plurality of gear trains for
odd-ordinal gear positions and even-ordinal gear positions; and a
pair of clutches linked to said odd-ordinal and even-ordinal gear
position gear trains, respectively, wherein: said transmission
mechanism is capable of power transmission by selectively using one
of said plurality of gear trains through a process in which a slide
member rotated as one body with a support shaft in each of said
plurality of gear trains is mutually non-rotatably engaged with a
free gear mutually rotatable in relation to said support shaft; one
of said clutches is engaged and the other of said clutches is
disengaged during a normal operation with a fixed gear position so
as to transmit power by use of one of said plurality of gear trains
linked to said engaged clutch and to develop a condition where
power transmission can be performed by use of a preliminarily
selected one of said plurality of gear trains linked to said
disengaged clutch; starting from this condition, said engaged
clutch is disengaged and said disengaged clutch is engaged so as to
perform changeover between said odd-ordinal gear position and said
even-ordinal gear position; at the time of said changeover of said
gear position, said formerly disengaged clutch is preliminarily
moved by a minute amount toward the clutch engaging side; and at
the time of said changeover of said gear position, at the time an
oil pressure supplied to said formerly disengaged clutch and an oil
pressure supplied to said formerly engaged clutch reach a same
level, the oil pressure supplied to said formerly disengaged clutch
starts to keep the same level for a period of time.
2. The twin clutch type speed change control system as set forth in
claim 1, wherein each of said clutches is an oil hydraulic clutch
that exhibits an engaging force based on an oil pressure supplied
externally, and, at the time of changeover of said gear position,
said formerly disengaged clutch is preliminarily supplied with a
minute oil pressure toward the clutch engaging side.
3. The twin clutch type speed change control system as set forth in
claim 1, wherein said formerly disengaged clutch is preliminarily
moved by the minute amount toward the clutch engaging side to
reduce a play in a rotating direction between said free gear and
said slide member.
4. The twin clutch type speed change control system as set forth in
claim 2, wherein said formerly disengaged clutch is preliminarily
moved by the minute amount toward the clutch engaging side to
reduce a play in a rotating direction between said free gear and
said slide member.
5. The twin clutch type speed change control system as set forth in
claim 1, wherein after said formerly disengaged clutch is
preliminarily moved by the minute amount toward the clutch engaging
side, said formerly disengaged clutch is moved until engaged.
6. The twin clutch type speed change control system as set forth in
claim 2, wherein after said formerly disengaged clutch is
preliminarily moved by the minute amount toward the clutch engaging
side, said formerly disengaged clutch is moved until engaged.
7. The twin clutch type speed change control system as set forth in
claim 1, wherein after said formerly disengaged clutch is
preliminarily moved by the minute amount toward the clutch engaging
side, said formerly engaged clutch is moved toward the clutch
disengaging side.
8. The twin clutch type speed change control system as set forth in
claim 2, wherein after said formerly disengaged clutch is
preliminarily moved by the minute amount toward the clutch engaging
side, said formerly engaged clutch is moved toward the clutch
disengaging side.
9. The twin clutch type speed change control system as set forth in
claim 1, wherein at the time the oil pressure supplied to said
formerly disengaged clutch and the oil pressure supplied to said
formerly engaged clutch reach the same level, the oil pressure
supplied to said formerly engaged clutch continues to decrease
until said formerly engaged clutch is fully disengaged.
10. The twin clutch type speed change control system as set forth
in claim 1, wherein the oil pressure supplied to said formerly
disengaged clutch keeps the same level until after a second period
of time after said formerly engaged clutch is fully disengaged.
11. A speed change control system comprising: a transmission
mechanism having a plurality of gear trains for odd-ordinal gear
positions and even-ordinal gear positions, each of said plurality
of gear trains including a slide member that is rotated as one body
with a support shaft, said slide member being mutually
non-rotatably engaged with a free gear that is mutually rotatable
in relation to said support shaft, said transmission mechanism
being capable of power transmission by selectively using one of
said plurality of gear trains; and a pair of clutches linked to
said odd-ordinal and even-ordinal gear position gear trains,
respectively, one of said clutches being engaged and the other of
said clutches being disengaged during a normal operation with a
fixed gear position so as to transmit power by use of one of said
plurality of gear trains that is linked to said engaged clutch, and
power transmission can be performed by use of a preliminarily
selected one of said plurality of gear trains linked to said
disengaged clutch, wherein said engaged clutch can be disengaged
and said disengaged clutch can engaged so as to perform changeover
between said odd-ordinal gear position and said even-ordinal gear
position, and, at the time of said changeover of said gear
position, said disengaged clutch is preliminarily moved by a minute
amount toward the clutch engaging side, and wherein at the time of
said changeover of said gear position, at the time an oil pressure
supplied to said disengaged clutch and an oil pressure supplied to
said engaged clutch reach a same level, the oil pressure supplied
to said disengaged clutch starts to keep the same level for a
period of time.
12. The twin clutch type speed change control system as set forth
in claim 11, wherein each of said clutches is an oil hydraulic
clutch that exhibits an engaging force based on an oil pressure
supplied externally, and, at the time of changeover of said gear
position, said disengaged clutch is preliminarily supplied with a
minute oil pressure toward the clutch engaging side.
13. The twin clutch type speed change control system as set forth
in claim 11, wherein said disengaged clutch is preliminarily moved
by the minute amount toward the clutch engaging side to reduce a
play in a rotating direction between said free gear and said slide
member.
14. The twin clutch type speed change control system as set forth
in claim 12, wherein said disengaged clutch is preliminarily moved
by the minute amount toward the clutch engaging side to reduce a
play in a rotating direction between said free gear and said slide
member.
15. The twin clutch type speed change control system as set forth
in claim 11, wherein after said disengaged clutch is preliminarily
moved by the minute amount toward the clutch engaging side, said
disengaged clutch is moved until engaged.
16. The twin clutch type speed change control system as set forth
in claim 12, wherein after said disengaged clutch is preliminarily
moved by the minute amount toward the clutch engaging side, said
disengaged clutch is moved until engaged.
17. The twin clutch type speed change control system as set forth
in claim 11, wherein after said disengaged clutch is preliminarily
moved by the minute amount toward the clutch engaging side, said
engaged clutch is moved toward the clutch disengaging side.
18. The twin clutch type speed change control system as set forth
in claim 10, wherein after said disengaged clutch is preliminarily
moved by the minute amount toward the clutch engaging side, said
engaged clutch is moved toward the clutch disengaging side.
19. The twin clutch type speed change control system as set forth
in claim 11, wherein at the time the oil pressure supplied to said
disengaged clutch and the oil pressure supplied to said engaged
clutch reach the same level, the oil pressure supplied to said
engaged clutch continues to decrease until said engaged clutch is
fully disengaged.
20. The twin clutch type speed change control system as set forth
in claim 11, wherein the oil pressure supplied to said disengaged
clutch keeps the same level until after a second period of time
after said engaged clutch is fully disengaged.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This nonprovisional application claims priority under 35 U.S.C.
.sctn.119(a) on Patent Application No. 2007-249813, filed in Japan
on Sep. 26, 2007, the entirety of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a twin clutch type speed change
control system suitable for use in a vehicle such as a
motorcycle.
2. Background of the Invention
Conventionally, there has been a twin clutch type speed change
control system including a transmission mechanism having a
plurality of gear trains for odd-ordinal gear positions and
even-ordinal gear positions, and a pair of clutches linked
respectively to both of the odd-ordinal and even-ordinal gear
position gear trains. The transmission mechanism is capable of
power transmission by selectively using one of the gear trains. One
of the clutches is engaged and the other of the clutches is
disengaged during a normal operation with a fixed gear position so
as to transmit power by use of one of the gear trains linked to the
engaged clutch and to develop a condition where power transmission
can be performed by use of a preliminarily selected one of the gear
trains linked to the disengaged clutch. Starting from this
condition, the engaged clutch is disengaged and the disengaged
clutch is engaged, whereby changeover between the odd-ordinal gear
position and the even-ordinal gear position is performed (refer to,
for example, Japanese Patent Laid-Open No. 2007-177904).
The transmission mechanism can perform power transmission by
selectively using one of the gear trains through a process in which
a slide member rotated as one body with a support shaft in each of
the gear trains is mutually non-rotatably engaged with a free gear
mutually rotatable in relation to the support shaft.
During the above-mentioned normal operation, in the disengaged
clutch, a component part on the drive source side is rotated idly
relative to a component part on the gear train side. In this
instance, the component part on the gear train side of the clutch
and a gear train contiguous to the component part are at stoppage
of rotation, and, at the time of changeover of the gear position, a
comparatively high rotational acceleration acts on the
preliminarily selected gear train. Therefore, between the free gear
and the slide member corresponding to this gear train, a collision
sound based on a mechanical play between these components may be
generated, and an improvement of this point is being demanded.
SUMMARY OF THE INVENTION
It is an object of the present invention to reduce the collision
sound generated between a free gear and a slide member at the time
of changeover of gear position, in a twin clutch type speed change
control system in which changeover of gear position is carried out
by switching between a pair of clutches.
As means to solve the above-mentioned problem, a first aspect of
the present invention is directed to a twin clutch type speed
change control system including a transmission mechanism (for
example, a transmission 47 in an embodiment) having a plurality of
gear trains (for example, speed change gear pairs 45a to 45f in the
embodiment) for odd-ordinal gear positions and even-ordinal gear
positions, and a pair of clutches (for example, first and second
disk clutches 51a and 52b in the embodiment) linked respectively to
both of the odd-ordinal and even-ordinal gear position gear trains,
the transmission mechanism being capable of power transmission by
selectively using one of the gear trains through a process in which
a slide member (for example, slide gears 48c, 48d, 49e, 49f in the
embodiment) rotated as one body with a support shaft (for example,
a main shaft 28 and a counter shaft 29 in the embodiment) in each
of the gear trains is mutually non-rotatably engaged with a free
gear (for example, free gears 48e, 48f, 49a to 49d in the
embodiment) mutually rotatable in relation to the support shaft;
and one of the clutches being engaged and the other of the clutches
being disengaged during a normal operation with a fixed gear
position so as to transmit power by use of one of the gear trains
linked to the engaged clutch and to develop a condition where power
transmission can be performed by use of a preliminarily selected
one of the gear trains linked to the disengaged clutch, and,
starting from this condition, the engaged clutch being disengaged
and the disengaged clutch being engaged so as thereby to perform
changeover between the odd-ordinal gear position and the
even-ordinal gear position; characterized in that at the time of
the changeover of the gear position, the formerly disengaged clutch
is preliminarily moved by a minute amount toward the clutch
engaging side.
According to a second aspect of the present invention, each of the
clutches is an oil hydraulic clutch which exhibits an engaging
force based on an oil pressure supplied externally, and, at the
time of changeover of the gear position, the formerly disengaged
clutch is preliminarily supplied with a minute oil pressure toward
the clutch engaging side.
According to a third aspect of the present invention, the formerly
disengaged clutch is preliminarily moved by a minute amount toward
the clutch engaging side to thereby reduce a play in a rotating
direction between the free gear and the slide member.
According to a fourth aspect of the present invention, after the
formerly disengaged clutch is preliminarily moved by a minute
amount toward the clutch engaging side, the formerly disengaged
clutch is moved until engaged.
According to a fifth aspect of the present invention, after the
formerly disengaged clutch is preliminarily moved by a minute
amount toward the clutch engaging side, the formerly engaged clutch
is moved toward the clutch disengaging side.
According to the present invention, at the time of changeover of
gear position (at the time of switching between the clutches), by
preliminarily moving the formerly disengaged clutch by a minute
amount toward the clutch engaging side, the preliminarily selected
gear train linked to this clutch is rotated under a minute torque,
whereby the play in the rotating direction between the free gear
and the slide member in the gear train can be reduced moderately,
which makes it possible to reduce the collision sound generated
between the free gear and the slide member due to the play at the
time of the subsequent changeover of the gear position.
Further scope of applicability of the present invention will become
apparent from the detailed description given hereinafter. However,
it should be understood that the detailed description and specific
examples, while indicating preferred embodiments of the invention,
are given by way of illustration only, since various changes and
modifications within the spirit and scope of the invention will
become apparent to those skilled in the art from this detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the
detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
FIG. 1 is a right side view of a motorcycle in an embodiment of the
present invention;
FIG. 2 is a right side view of an engine in the motorcycle;
FIG. 3 is a block diagram of a twin clutch type speed change
control system of the motorcycle;
FIG. 4 is a sectional view of a twin clutch type transmission of
the motorcycle;
FIG. 5 is a sectional view of a change mechanism for operating the
twin clutch type transmission;
FIG. 6 is a graph showing the condition in which clutch control oil
pressures in the twin clutch type speed change control system are
supplied; and
FIGS. 7(a)-7(c) illustrate the conditions of engagement between a
slide-side dog and a free-side dog in the twin clutch type
transmission, wherein FIG. 7(a) shows the condition during a normal
operation with a fixed gear position, FIG. 7(b) shows the condition
immediately before changeover of gear position, and FIG. 7(c) shows
the condition at the time of changeover of gear position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described in detail with
reference to the accompanying drawings, wherein the same reference
numerals will be used to identify the same or similar elements
throughout the several views. It should be noted that the drawings
should be viewed in the direction of orientation of the reference
numerals. Also, the front, rear, left, right and the like sides
(directions) in the following description are the same as the sides
(directions) with respect to a vehicle unless otherwise specified.
In addition, arrow FR in the drawings indicates the front side of
the vehicle, arrow LH indicates the left-hand side of the vehicle,
and arrow UP indicates the upper side of the vehicle.
As shown in FIG. 1, an upper part of a front fork 3 rotatably
supporting a front wheel 2 in a motorcycle (saddle ride type
vehicle) 1 is steerably supported by a head pipe 6 provided at a
front end part of a body frame 5, through a steering stem 4. A
steering handle 4a is attached to an upper part of the steering
stem 4 (or the front fork 3). From the head pipe 6, a main frame 7
extends rearwards, to be connected to pivot plates 8. Front end
parts of swing arms 9 are vertically swingably supported on the
pivot plates 8, and a rear wheel 11 is rotatably supported on rear
end parts of the swing arms 9. A cushion unit 12 is interposed
between the swing arm 9 and the body frame 5. On the inner side of
the body frame 5, an engine (internal combustion engine) 13 as a
prime mover of the motorcycle 1 is suspended.
Referring to FIG. 2, the engine 13 is a parallel four-cylinder
engine with a rotational center axis C1 of a crankshaft 21 set in
the vehicle width direction (left-right direction), wherein
cylinders 15 are erectly provided on a crankcase 14, a
corresponding piston 18 is reciprocatably fitted in each of the
cylinders 15. Reciprocation of each piston 18 is converted into
rotation of the crankshaft 21 through connecting rods 19. A
throttle body 16 is connected to a rear part of the cylinder 15. An
exhaust pipe 17 is connected to a front part of the cylinder
15.
A transmission case 22 is provided on the rear side of and
integrally with the crankcase 14. A twin clutch type transmission
23 and a change mechanism 24 are contained in the transmission case
22. A right side part of the transmission case 22 is made to be a
clutch case 25. Twin clutches 26 of the twin clutch type
transmission 23 are contained in the clutch case 25. Rotational
power of the crankshaft 21, serving as a motive power source of the
engine 13, is outputted to the left side of the transmission case
22 through the twin clutch type transmission 23, and is transmitted
to the rear wheel 11 through a power transmission mechanism of a
chain type, for example. Incidentally, symbols C2 and C3 in the
figure respectively denote rotational center axes of a main shaft
28 and a counter shaft 29 of the twin clutch type transmission
23.
As shown in FIG. 3, the motorcycle 1 is provided with a twin clutch
type speed change control system which mainly includes the twin
clutch type transmission 23 provided in connection with the engine
13, a gear shift device 41 configured by providing the change
mechanism 24 with a driving mechanism 39, and an electronic control
unit (ECU) 42 for controlling the operations of the twin clutch
type transmission 23 and the gear shift device 41.
Referring to FIG. 4 also, the twin clutch type transmission 23
includes the main shaft 28 having a double structure composed of
inner and outer shafts 43, 44. The counter shaft 29 is disposed in
parallel to the main shaft 28. A speed change gear group 45 is
disposed bridgingly between the main shaft 28 and the counter shaft
29. The twin clutches 26 are coaxially disposed at a right end part
of the main shaft 28. An oil pressure supply system 46 supplies a
working oil pressure to the twin clutches 26. Hereinafter, the
assembly composed of the main shaft 28, the counter shaft 29 and
the speed change gear group 45 is referred to as transmission
47.
The main shaft 28 has a structure in which a right end part of the
inner shaft 43 extending bridgingly between left and right parts of
the transmission case 22 is mutually rotatably inserted in the
outer shaft 44. On the outer peripheries of the inner and outer
shafts 43, 44, drive gears 48a to 48f for six gear speeds in the
speed change gear group 45 are distributedly disposed. On the other
hand, driven gears 49a to 49f for six gear speeds in the speed
change gear group 45 are disposed on the outer periphery of the
counter shaft 29. The drive gears 48a to 48f and the driven gears
49a to 49f are meshed with each other on the basis of each gear
position, to constitute speed change gear pairs 45a to 45f
corresponding to the gear positions, respectively. Incidentally,
the speed change gear pairs 45a to 45f are decreased in reduction
gear ratio (are higher-speed gears increased in speed) in the order
of from 1st gear speed to 6th gear speed.
A left end part of the inner shaft 43 reaches a left side wall 22a
of the transmission case 22, and is rotatably borne on the left
side wall 22a through a ball bearing 73.
On the other hand, a right side part of the inner shaft 43
penetrates a right side wall 22b of the transmission case 22 to be
exposed inside the clutch case 25. An intermediate part in the
left-right direction of the inner shaft 43 is rotatably borne on
the right side wall 22b of the transmission case 22 through an
intermediate part in the left-right direction of the outer shaft 44
penetrating the right side wall 22b and through a ball bearing
77.
The outer shaft 44 is shorter than the inner shaft 43, and a left
end part thereof is terminated at an intermediate part in the
left-right direction of the transmission case 22. On that portion
of the outer shaft 44 that is located on the left side relative to
the right side wall 22b, the driven gears 48b, 48d and 48f
corresponding to even-ordinal gear positions (2nd, 4th and 6th
speeds) in the speed change gear group 45 are supported in the
order of 4th speed, 6th speed and 2nd speed from the left side. On
the other hand, on that portion of the inner shaft 43 that is
located on the left side of a left end part of the outer shaft 44,
the drive gears 48a, 48c and 48e corresponding to odd-ordinal gear
positions (1st, 3rd and 5th speeds) in the speed change gear group
45 are supported in the order of 1st speed, 5th speed and 3rd speed
from the left side.
Left and right end parts of the counter shaft 29 are rotatably
borne on the left and right side walls 22a, 22b of the transmission
case 22 through ball bearings 82, 86, respectively. The left end
part of the counter shaft 29 protrudes to the left side of the left
side wall 22a, and a drive sprocket 83 of the power transmission
mechanism for transmission of power to the rear wheel 11 is
attached to the left end part.
The driven gears 49a to 49f in the speed change gear group 45
corresponding respectively to the gear positions are borne on that
portion of the counter shaft 29 which are located on the inner side
of the transmission case 22, in the same order as the drive gears
48a to 48f.
Main feed oil passages 71, 72 capable of supplying an oil pressure
from a main oil pump (not shown) for pressure feed of an oil to
parts in the engine 13 are formed respectively in the main shaft 28
(inner shaft 43) and the counter shaft 29. Engine oil is
appropriately supplied to the speed change gear group 45 through
the main oil passages 71, 72.
The twin clutches 26 have oil hydraulic type first and second disk
clutches (hereinafter they will in some cases be referred to simply
as clutches) 51a, 51b disposed coaxially with and adjacently to
each other. The inner and outer shafts 43, 44 are coaxially
connected respectively to the clutches 51a, 51b. A primary driven
gear 58 meshed with a primary drive gear 58a on the crankshaft 21
is coaxially provided on a clutch outer 56 possessed in common by
the clutches 51a, 51b. A rotational drive force from the crankshaft
21 is inputted to the clutch outer 56 through the gears 58, 58a.
The rotational drive force inputted to the clutch outer 56 is
transmitted individually to the inner and outer shafts 43, 44
according to the engaged/disengaged conditions of the clutches 51a,
51b. The engaged/disengaged conditions of the clutches 51a, 51b are
individually controlled by the presence/absence of an oil pressure
supplied from the above-mentioned oil pressure supply system
46.
One of the clutches 51a, 51b is engaged whereas the other is
disengaged. Power transmission in the transmission 47 is performed
by use of one of the speed change gear pair linked to one of the
inner and outer shafts 43, 44. In addition, the speed change gear
pair to be used next is preliminarily selected from among the speed
change gear pairs linked to the other of the inner and outer shafts
43, 44. Starting from this condition, one of the clutches 51a, 51b
is disengaged whereas the other is engaged, whereby the power
transmission in the transmission 47 is changed over to that made by
use of the preliminarily selected speed change gear pair, resulting
in upshift or downshift in the transmission 47.
As shown in FIG. 3, the oil pressure supply system 46 includes a
clutch oil pump 32 as an oil pressure generation source for the
twin clutches 26. A feed oil passage 35 extends from a discharge
port of the clutch oil pump 32. First and second clutch actuators
91a, 91b are connected to the downstream side of the feed oil
passage 35. First and second supply oil passages 92a, 92b extend
from the clutch actuators 91a, 91b to engaging-side oil pressure
chambers 54a, 54b (see FIG. 4) of the clutches 51a, 51b.
The clutch oil pump 32 is provided separately from the main oil
pump, and operates to suck in the engine oil reserved in an oil pan
36 on the lower side of the crankcase 14 and to discharge the oil
into the feed oil passage 35. An oil filter 89 for exclusive use in
the oil passage is provided in the feed oil passage 35.
Incidentally, symbols S6 and S7 in the figure identify an oil
pressure sensor and an oil temperature sensor for detecting the oil
pressure and the oil temperature in the feed oil passage 35,
respectively. Symbol R identifies a relief valve for controlling
the rise in the oil pressure inside the feed oil passage 35.
Symbols S8, S9 identify oil pressure sensors for detecting the oil
pressures in the supply oil passages 92a, 92b, respectively, i.e.,
the pressures of the oil fed to the clutches 51a, 51b,
respectively.
Communication of the feed oil passage 35 and the first and second
supply oil passages 92a, 92b can be individually made by operations
of the clutch actuators 91a, 91b. When the feed oil passage 35 and
the first supply oil passage 92a are made to communicate with each
other through the first clutch actuator 91a, a comparatively high
oil pressure from the clutch oil pump 32 is supplied through the
first supply oil passage 92a into the engaging-side oil pressure
chamber 54a of the first clutch 51a, whereby the first clutch 51a
is engaged. On the other hand, when the feed oil passage 35 and the
second supply oil passage 92b are made to communicate with each
other through the second clutch actuator 91b, the oil pressure from
the clutch oil pump 32 is supplied through the second supply oil
passage 92b into the engaging-side oil pressure chamber 54b of the
second clutch 51b, whereby the second clutch 51b is engaged.
An oil pressure relief oil passage 96a provided with an oil
pressure relief valve 95 is branched from the feed oil passage 35.
The oil pressure relief valve 95 is operated by a valve actuator
95a to make changeover between opening and closing of the oil
pressure relief oil passage 96a. The valve actuator 95a is
controlled by the electronic control unit 42 so as to operate as
follows. For example, at the time of starting the engine, the valve
actuator 95a opens the oil pressure relief oil passage 96a, whereby
the feed oil pressure from the clutch oil pump 32 is returned into
the oil pan 36, and, after the starting of the engine, the valve
actuator 95a closes the oil pressure relief oil passage 96a so that
the feed oil pressure can be supplied to the twin clutches 26.
Incidentally, the clutch actuators 91a, 91b are provided
respectively with return oil passages 93a, 93b for returning the
oil pressure from the clutch oil pump 32 into the oil pan when the
communication between the feed oil passage 35 and the first and
second supply oil passages 92a, 92b is interrupted.
As shown in FIGS. 3 and 5, the change mechanism 24 moves in the
axial direction a plurality of (in this embodiment, four) shift
forks 24b by rotation of a shift drum 24a disposed in parallel to
the shafts 28, 29, whereby the speed change gear pair (gear
position) used for power transmission between the main shaft 28 and
the counter shaft 29 is changed over.
Of the shift forks 24b, one that extends to the side of the main
shaft 28 and one that extends to the side of the counter shaft 29
constitute a pair. The base end sides of the shift forks 24b are
axially movably supported by a pair of shift fork rods 24c,
respectively. Each of the shift forks 24b is provided on the base
end side thereof with a slide projection 24e for engagement with
one of a plurality of cam grooves 24d provided in the outer
periphery of the shift drum 24a. Each of the shift forks 24b has
tip parts thereof engaged with a slide gear (described later) in
the speed change gear group 45, on the side of the main shaft 28
and on the side of the counter shaft 29. At the time of rotation of
the shift drum 24a, each shift fork 24b is moved in the axial
direction according to the pattern of each cam groove 24d, and the
slide gear is moved in the axial direction, whereby the gear
position in the transmission 47 is changed.
The above-mentioned drive mechanism 39 is provided on one end side
of the shift drum 24a. The drive mechanism 39 includes a pin gear
39a coaxially fixed to the shift drum 24a in the change mechanism
24. A worm-shaped barrel cam 39b is engaged with the pin gear 39a.
An electric motor 39c provides a rotational drive force to the
barrel cam 39b. By driving the electric motor 39c, the shift drum
24a is rotated appropriately, whereby the gear position in the
transmission 47 is changed.
Incidentally, symbol S1 in the figure identifies a sensor for
detecting the operating (moving) amount of the drive mechanism 39
for detecting the gear position in the transmission 47. Symbol DS
identifies a rotational angle sensor for detecting the actual
rotating angle of the shift drum 24a. Symbol DT identifies a detent
for restricting the rotating angle on a gear position basis of the
shift drum 24a.
As shown in FIG. 4, the transmission 47 is of the normally meshed
type in which each of the drive gears 48a to 48f and each of the
driven gears 49a to 49f corresponding to each of the gear positions
are normally meshed with each other. The gears are largely
classified into fixed gears being rotatable integrally with the
relevant support shaft (each of the shafts 28, 29), free gears
being mutually rotatable in relation to the support shaft, and
slide gears being integrally rotatable and axially movable in
relation to the shaft.
Specifically, the drive gears 48a, 48b are fixed gears; the drive
gears 48c, 48d are slide gears; and the drive gears 48e, 48f are
free gears. In addition, the driven gears 49a to 49d are free
gears, and the driven gears 49e, 49f are slide gears. Hereinafter,
the gears 48c, 48d, 49e, 49f will be referred to as the slide
gears, and the gears 48e, 48f, 49a to 49d will be referred to as
the free gears.
Then, with arbitrary ones of the slide gears being appropriately
slid (moved in the axial direction) by the change mechanism 24,
power transmission by use of the speed change gear pair
corresponding to one of the gear position is enabled.
On one side of the slide gears 48c, 48d, slide rings Sc, Sd, being
integrally rotatable and axially movable in relation to the
relevant support shaft in the same manner as the slide gears 48c,
48d, are provided integrally with the latter. The slide rings Sc,
Sd are provided axially adjacently to the free gears 48e, 48f,
respectively. The slide rings Sc, Sd are provided respectively with
slide-side dogs (dowels) D1c, D1d, whereas the free gears 48e, 45f
are provided respectively with free-side dogs (dowels) D1e, D1f
corresponding respectively to the slide-side dogs D1c, D1d.
In addition, on one side of the slide gears 49e, 49f, slide rings
Se, Sf, being integrally rotatable and axially movable in relation
to the relevant support shaft in the same manner as the slide gears
49e, 49f, are provided integrally with the latter. The slide rings
Se, Sf are provided axially adjacently to the free gears 49c, 49d,
respectively. The slide rings Se, Sf are provided respectively with
slide-side dogs (dowels) D2e, D2f, whereas the free gears 49c, 49d
are provided respectively with free-side dogs (dowels) D2c, D2d
corresponding respectively to the slide-side dogs D2e, D2f.
Furthermore, slide-side dogs (dowels) D3e, D3f are provided on the
other side of the slide gears 49e, 49f. The free gears 49a, 49b
axially adjacent to the slide-side dogs D3e, D3f are provided
respectively with free-side dogs (dowels) D3a, D3b corresponding
respectively to the slide-side dogs D3e, D3f.
The slide-side dog and the free-side dog are mutually non-rotatably
engaged with each other when the corresponding slide gear
(inclusive of the slide ring) and free gear come close to each
other. The engagement is canceled when the corresponding slide gear
and free gear are separated away from each other.
Then, with one of the slide gears and the corresponding free gear
being mutually non-rotatably engaged with each other through the
dog, power transmission by selective use of one of the speed change
gear pair between the main shaft 28 and the counter shaft 29 is
enabled.
Incidentally, in the condition where the engagements between the
slide gears and the corresponding free gears are all canceled (in
the condition shown in FIG. 4), the power transmission between the
shafts 28 and 29 is disabled. This condition is a neutral condition
of the transmission 47.
As shown in FIG. 3, based not only on the data from the
above-mentioned sensors but also on the data from a throttle valve
position sensor TS for the throttle body 16, a side stand (or
center stand) storage sensor (switch) SS, a wheel speed sensor WS
for the front wheel 2 as well as, for example, a mode switch SW1, a
gear selection switch SW2, and a neutral-drive changeover switch
SW3 provided on the steering handle 4a, etc., the electronic
control unit 42 controls the operations of the twin clutch type
transmission 23 and the gear shift device 41, thereby changing the
gear position (shift position) in the transmission 47.
The speed change mode selected by operating the mode switch SW1
includes a full-automatic mode in which the gear position in the
transmission 47 is automatically changed over based on vehicle data
such as vehicle speed (wheel speed) and engine speed, and a
semi-automatic mode in which the gear position in the transmission
47 can be changed over only by operation of the selection switch
SW2 based on the driver's will. The current speed change mode and
gear position are displayed, for example, on a meter device M
provided in the vicinity of the steering handle 4a. In addition, by
operation of the neutral-drive switch SW3, the transmission 47 can
be changed over between a condition where power transmission at a
predetermined gear position is possible and the neutral
condition.
Incidentally, symbol S2 in the figure identifies a vehicle speed
sensor for detecting the rotating speed of the main shaft 28
(detecting the rotating speed of the drive gear 48e meshed with the
driven gear 49e rotated as one body with the counter shaft 29) for
detecting the vehicle speed. Symbol S3 identifies a rotating speed
sensor for detecting the rotating speed of the primary driven gear
58 for detecting the engine speed (the rotating speed of the
crankshaft 21). The electronic control unit 42 shares the data from
the sensors with an ECU 42a for a fuel injection system.
As shown in FIG. 4, the twin clutches 26 have a structure in which
the first clutch 51a linked to the speed change gear pairs for
odd-ordinal gear positions is disposed on the right side (on the
outer side in the vehicle width direction) in the clutch case 25.
The second clutch 51b linked to the speed change gear pairs for
even-ordinal gear positions is disposed on the left side (on the
inner side in the vehicle width direction) in the clutch case 25.
The clutches 51a, 51b are each a wet-type multiple disk clutch
having a plurality of clutch disks (clutch disks 61a, 61b and
clutch plates 66a, 66b) overlapping alternately in the axial
direction.
Each of the clutches 51a, 51b is of an oil hydraulic type in which
the pressure plate 52a, 52b is displaced in the axial direction by
a supply oil pressure supplied externally, thereby obtaining a
predetermined engaging force. Each of the clutches 51a, 51b
includes a return spring 53a, 53b for urging the pressure plate
52a, 52b toward the clutch disengaging side. The engaging-side oil
pressure chamber 54a, 54b exerts a pushing force toward the clutch
engaging side on the pressure plate 52a, 52b. A disengaging-side
oil pressure chamber 55a, 55b exerts a pushing force toward the
clutch disengaging side on the pressure plate 52a, 52b so as to
assist the returning motion of the latter.
Each of the disengaging-side oil pressure chambers 55a, 55b is
normally supplied with a comparatively low oil pressure from the
above-mentioned main oil pump. The engaging-side oil pressure
chambers 54a, 54b are selectively and individually supplied with a
comparatively high oil pressure from the oil pressure supply system
46 (the clutch oil pump 32).
The clutches 51a, 51b share the single clutch outer 56 with each
other, and are configured to be substantially equal in diameter.
The clutch outer 56 is in the shape of a bottomed cylinder opened
to the right side, A central part of a bottom part thereof is
mutually rotatably supported by an intermediate part in the
left-right direction of the outer shaft 44. A clutch center 57a for
the first clutch 51a is disposed on the left inner side of the
clutch outer 56. A clutch center 57b for the second clutch 51b is
disposed on the right inner side of the clutch outer 56. The clutch
center 57a is integrally rotatably supported on a right end part of
the inner shaft 43. The clutch center 57b is integrally rotatably
supported on a right end part of the outer shaft 44.
The primary driven gear 58 is mounted to the left side of a bottom
part of the clutch outer 56, with a spring damper 59 therebetween.
The primary driven gear 58 is meshed with the primary drive gear
58a of the crankshaft 21. Therefore, a rotational power of the
crankshaft 21 is inputted to the clutch outer 56 through the spring
damper 59. The clutch outer 56 is rotated attendant on the rotation
of the crankshaft 21 and separately from the main shaft 28.
A drive sprocket 56b for driving each oil pump is integrally
rotatably provided on the left side, relative to the primary driven
gear 58 of the clutch outer 56. A plurality of the clutch plates
61a for the first clutch 51a are integrally rotatably supported on
the right inner periphery of the clutch outer 56. A plurality of
the clutch plates 61b for the second clutch 51b are integrally
rotatably supported on the left inner periphery of the clutch outer
56.
The clutch outer 56 is provided in its outer periphery with a
plurality of engaging grooves along the axial direction. The clutch
plates 61a, 61b are each provided at the outer periphery thereof
with a plurality of engaging projections corresponding to the
engaging grooves. The engaging projections are mutually
non-rotatably engaged with the engaging grooves, whereby the clutch
plates 61a, 61b are integrally rotatably supported on the clutch
outer 56.
A flange part 64a on the left side of the clutch center 57a of the
first clutch 51a is provided with an inner wall part 65a erecting
rightwards. A plurality of the clutch disks (friction plates) 66a
are integrally rotatably supported on the outer periphery of the
inner wall part 65a.
The clutch center 57a is provided in an outer periphery thereof
with a plurality of engaging grooves along the axial direction.
Each of the clutch disks 66a is provided at an inner periphery
thereof with a plurality of engaging projections corresponding to
the engaging grooves. The engaging projections are mutually
non-rotatably engaged with the engaging grooves, whereby the clutch
disks 66a are integrally rotatably supported on the clutch center
57a.
The above-mentioned pressure plate 52a is opposedly disposed on the
right side of the flange part 64a. Between the outer periphery side
of the pressure plate 52a and the outer periphery side of the
flange part 64a, the above-mentioned clutch plates 61a and clutch
disks 66a are disposed in the state of being alternately stacked in
the axial direction.
Between the inner periphery side of the pressure plate 52a and the
inner periphery side of the flange part 64a, the above-mentioned
disengaging-side oil pressure chamber 55a is formed and the return
spring 53a for urging the pressure plate 52a to the right side (to
the side for spacing away from the flange part 64a, i.e., to the
clutch disengaging side) is disposed.
A support flange part 67a provided at the outer periphery of a
central tubular part 62a on the right side of the clutch center 57a
is opposedly disposed on the right side of the inner periphery side
of the pressure plate 52a. The above-mentioned engaging-side oil
pressure chamber 54a is formed and the return spring 53a is
disposed between the support flange part 67a and the inner
periphery side of the pressure plate 52a.
On the other hand, a flange part 64b on the left side of the clutch
center 57b of the second clutch 51b is provided with an inner wall
part 65b erecting rightwards. A plurality of the clutch disks 66b
are integrally rotatably supported on the outer periphery of the
inner wall part 65b.
The clutch center 57b is provided in its outer periphery with a
plurality of engaging grooves along the axial direction. Each of
the clutch disks 66b is provided at an inner periphery thereof with
a plurality of engaging projections corresponding to the engaging
grooves. The engaging projections are mutually non-rotatably
engaged with the engaging grooves, whereby the clutch disks 66b are
integrally rotatably supported on the clutch center 57b.
The above-mentioned pressure plate 52b is opposedly disposed on the
right side of the flange part 64b. The above-mentioned clutch
plates 61b and clutch disks 66b are disposed in the state of being
alternately stacked in the axial direction, between the outer
periphery side of the pressure plate 52b and the outer periphery
side of the flange part 64b.
The above-mentioned disengaging-side oil pressure chamber 55b is
formed and a return spring 53b for urging the pressure plate 52b to
the right side (to the side for spacing away from the flange part
64b, i.e., to the clutch disengaging side) is disposed between the
inner periphery side of the pressure plate 52b and the inner
periphery side of the flange part 64b.
A support flange part 67b provided at the outer periphery of a
central tubular part 62b on the right side of the clutch center 57b
is opposedly disposed on the right side on the inner periphery side
of the pressure plate 52b. The above-mentioned engaging-side oil
pressure chamber 54b is formed and the return spring 53b is
disposed between the support flange part 67b and the inner
periphery side of the pressure plate 52b.
A clutch cover 69 constituting the right side of the
above-mentioned clutch case 25 is provided with a first supply oil
passage 92a, a second supply oil passage 92b, and an in-cover main
supply oil passage 71a. In addition, oil passages communicating
individually with the oil passages 92a, 92b, 71a are appropriately
formed in a right hollow part 43a of the inner shaft 43.
As a result, an oil pressure from the clutch oil pump 32 can be
supplied through the first supply oil passage 92a and the like into
the engaging-side oil pressure chamber 54b of the second clutch
51b. An oil pressure from the above-mentioned main oil pump can be
supplied through the in-cover main supply oil passage 71 and the
like into the disengaging-side oil pressure chamber 55a of the
first clutch 51a. An oil pressure from the clutch oil pump 32 can
be supplied through the second supply oil passage 92b and the like
into the engaging-side oil pressure chamber 54a of the first clutch
51a. Incidentally, the disengaging-side oil pressure chamber 55b of
the second clutch 51b can be supplied with an oil pressure from the
main oil pump through the main supply oil passage 71 and the
like.
In the condition where the engine is stopped (in the condition
where the oil pumps are stopped), the clutches 51a, 51b are in the
disengaged condition wherein the pressure plates 52a, 52b are
displaced to the right side by the urging forces of the return
springs 53a, 53b, and the frictional engagement between the clutch
plates 61a, 61b and the clutch disks 66a, 66b is canceled. In the
condition where the engine is in operation and the supply of the
oil pressure from the oil pressure supply system 46 is stopped, the
urging forces of the return springs 53a, 53b and the oil pressures
in the disengaging-side oil pressure chambers 55a, 55b act on the
pressure plates 52a, 52b, whereby the clutches 51a, 51b are again
put in the disengaged condition.
On the other hand, in the condition where the engine is in
operation and a comparatively high oil pressure is supplied from
the oil pressure supply system 46 into the engaging-side oil
pressure chamber 54a in the first clutch 51a, the pressure plate
52a is moved to the left side (to the flange part 64a side, i.e.,
to the clutch engaging side) against the oil pressure in the
disengaging-side oil pressure chamber 55a and the urging force of
the return spring 53a, and the clutch plates 61a and the clutch
disks 66a are pressed into frictional engagement with each other,
resulting in the clutch engaged condition wherein torque
transmission between the clutch outer 56 and the clutch center 57a
is possible.
Similarly, in the condition where the engine is in operation and a
comparatively high oil pressure is supplied from the oil pressure
supply system 46 into the engaging-side oil pressure chamber 54b in
the second clutch 51b, the pressure plate 52b is moved to the left
side (to the flange part 64b side, i.e., to the clutch engaging
side) against the oil pressure in the disengaging-side oil pressure
chamber 55b and the urging force of the return spring 53b, and the
clutch plate 61b and the clutch disks 66b are pressed into
frictional engagement with each other, resulting in the clutch
engaged condition wherein torque transmission between the clutch
outer 56 and the clutch center 57b is possible.
Incidentally, when the supply of the oil pressure into the
engaging-side oil pressure chamber 54a, 54b is stopped under the
condition where the clutch 51a, 51b is in the engaged condition,
the pressure plate 52a, 52b is displaced to the left side by the
oil pressure in the disengaging-side oil pressure chamber 55a, 55b
and the urging force of the return spring 53a, 53b, and the
frictional engagement between the clutch plates 61a, 61b and the
clutch disks 66a, 66b is canceled, resulting in the clutch
disengaged condition wherein torque transmission between the clutch
outer 56 and the clutch center 57a, 57b is impossible.
The engine oil supplied into the disengaging-side oil pressure
chamber 55a, 55b of the clutch 51a, 51b is guided to the exterior
of the oil pressure chamber through the oil passages formed
appropriately in the inner wall part 65a, 65b and the like, thereby
being appropriately supplied to the clutch plates 61a, 61b and the
clutch disks 66a, 66b at the outer periphery of the inner wall part
65a, 65b. By thus relieving the working oil present in the
disengaging-side oil pressure chamber 55a, 55b, the oil pressure
inside the disengaging-side oil pressure chamber 55a, 55b is kept
at a predetermined low pressure, and the lubrication performance
and the cooling performance in regard of the clutch plates 61a, 61b
and the clutch disks 66a, 66b in the clutch 51a, 51b in the
disengaged condition are enhanced.
In the twin clutch type transmission 23, in the case where the
motorcycle 1 is judged as being stopped on the basis of the side
stand being erecting or the like fact even after the engine is
started, both of the clutches 51a and 51b are kept in the
disengaged condition. Then, when for example the side stand is
stored or the switch SW1, SW2 or SW3 is operated, the transmission
47 is shifted from the neutral condition to a 1st gear speed
condition such as to enable power transmission by use of the 1st
gear (starting gear, i.e., the speed change gear pair 45a) as a
preparation for starting the motorcycle 1, and, when for example
the engine speed is raised starting from this condition, the first
clutch 51a is brought through a half-clutch condition into the
engaged condition, whereby the motorcycle 1 is started.
During the running of the motorcycle 1, only one of the clutches
51a, 51b is in the engaged condition depending on the current shift
positions thereof, whereas the other is kept disengaged. As a
result, power is transmitted through one of the inner and outer
shafts 43, 44 and one of the speed change gear pairs 45a to 45f. In
this case, the electronic control unit 42 controls the operation of
the twin clutch type transmission 23 on the basis of vehicle data,
so as to preliminarily prepare a condition where power transmission
by use of a speed change gear pair corresponding to the next shift
position is possible.
Specifically, where the current shift position (gear position) is
for example an odd-ordinal gear position (or even-ordinal gear
position), the next shift position is an even-ordinal gear position
(or odd-ordinal gear position). In this case, therefore, a
condition where power transmission by use of a speed change gear
pair for the even-ordinal gear position (or odd-ordinal gear
position) is possible is preliminarily developed.
In this instance, the first clutch 51a is in the engaged condition,
but the second clutch 51b (or the first clutch 56a) is in the
disengaged condition, so that the engine output (the rotational
power of the crankshaft 21) is not transmitted to the outer shaft
44 (or the inner shaft 43) and the speed change gear pair for the
even-ordinal gear position (or odd-ordinal gear position).
Thereafter, when the electronic control unit 42 judges that a
timing for gear shift is reached, the first clutch 51a (or the
second clutch 51b) is disengaged and the second clutch 51b (or the
first clutch 51a) is engaged, simply, whereby the power
transmission is changed over to one for transmitting power by use
of the speed change gear pair corresponding to the next shift
position which has preliminarily been selected. Accordingly, it is
possible to achieve a swift and smooth speed change, without any
time lag in speed change and without any interruption of power
transmission.
As shown in FIG. 6, at the time of changeover of the gear position
in the transmission 47 (at the time of switching between the
clutches 51a and 51b), a minute oil pressure P1 is supplied into
the engaging-side oil pressure chamber of the clutch (51a or 51b)
which has been in the disengaged condition immediately before the
changeover of gear position, whereby the clutch is moved by a
minute amount to the engaging side. Incidentally, the minute oil
pressure P1 means an oil pressure of not less than the minimum oil
pressure necessary for reducing the mechanical play in the clutch
(an oil pressure of not less than the oil pressure corresponding to
the force of the return spring in the clutch).
In addition, the time immediately before the changeover of gear
position means the time ranging from a timing T1 before the timing
T2 of supplying an ordinary engaging oil pressure P2 to the clutch
in the disengaged condition to the timing T2. In other words, the
time ranging from the timing T1 before the timing T3 of removing
the ordinary engaging oil pressure P2 in the clutch in the engaged
condition to the timing T3. Incidentally, the timings T2 and T3 may
have a time difference therebetween or may be the same.
During a normal operation with a fixed gear position, in the clutch
in the engaged condition (engaged-side clutch), component parts on
the crankshaft 21 side (the component parts rotated as one body
with the primary driven gear 58, i.e., the clutch outer 56, and the
clutch plates 61a, 61b, and the like) and component parts on the
transmission 47 side (the component parts rotated as one body with
the main shaft 28, i.e., the clutch center 57a or 57b, and the
clutch disks 66a, 66b, and the like) are rotated integrally with
each other.
On the other hand, during the normal operation, in the clutch in
the disengaged condition (disengaged-side clutch), component parts
on the crankshaft 21 side are rotated idly in relation to component
parts on the side of the transmission 47 being in the stopped
state. In this case, the speed change gear pair contiguous on the
transmission 47 side of the clutch is also stopped from
rotating.
Referring to FIG. 7(a), during power transmission in the
transmission 47 (for example, during a normal operation with a
fixed gear position), in the speed change gear pair for power
transmission which is linked to the engaged-side clutch, the
slide-side dogs (generically denoted by symbol SD in FIG. 7) of the
slide gears (generically denoted by symbol SG in FIG. 7) and the
free-side dogs (generically denoted by symbol FD in FIG. 7) of the
free gears (generically denoted by FG in FIG. 7) abut on each other
in the rotating direction, thereby to transmit a driving force. On
the other hand, in the preliminarily selected speed change gear
pair linked to the disengaged-side clutch, a mechanical play in the
rotating direction is generated between the slide-side dogs SD and
the free-side dogs FD.
At the time of a changeover of gear position, the disengaged-side
clutch is moved by a minute amount toward the clutch engaging side
immediately before the changeover, whereby a minute torque is
exerted on the preliminarily selected speed change gear pair linked
to the clutch. Also, the play in the rotating direction between the
dogs SD and FD in the speed change gear pair is moderately reduced,
resulting in abutment of the dogs SD and FD on each other (see FIG.
7(b)).
Thereafter, the disengaged-side clutch is put into the ordinary
engaged condition, whereas the engaged-side clutch is put into the
disengaged condition, whereby the gear position in the transmission
47 can be changed over while suppressing the collision sound
between the dogs SD and FD in the preliminarily selected speed
change gear pair (see FIG. 7(c)).
As has been described above, the twin clutch type speed change
control system in the embodiment above includes the transmission 47
having the plurality of speed change gear pairs 45a to 45f for
odd-ordinal gear positions and even-ordinal gear positions. The
pair of oil hydraulic type multiple disk clutches 51a, 51b are
linked respectively to both the odd-ordinal and even-ordinal gear
position speed change gear pairs, the transmission 47 being capable
of power transmission by selectively using one of the speed change
gear pairs through a process in which the slide gear 48c, 48d, 49e,
49f rotated as one body with the support shaft (the main shaft 28
or the counter shaft 29) in each of the speed change gear pairs are
mutually non-rotatably engaged with the free gear 48e, 48f, 49a to
49d mutually rotatable in relation to the support shaft; and one of
the clutches 51a, 51b being engaged and the other being disengaged
during a normal operation with a fixed gear position so as to
transmit power by use of one of the speed change gear pairs linked
to the engaged clutch and to develop a condition where power
transmission can be performed by use of a preliminarily selected
one of the speed change gear pairs linked to the disengaged clutch,
and, starting from this condition, the engaged clutch being
disengaged and the disengaged clutch being engaged so as thereby to
perform changeover between the odd-ordinal gear position and the
even-ordinal gear position; wherein at the time of the changeover
of the gear position, the formerly disengaged clutch is
preliminarily supplied with a minute oil pressure P1 toward the
clutch engaging side, whereby the formerly disengaged clutch is
moved by a minute amount toward the clutch engaging side.
According to this configuration, at the time of changeover of the
gear position (at the time of switching between the clutches 51a
and 51b), the formerly disengaged clutch is preliminarily moved by
a minute amount toward the clutch engaging side, whereby a minute
torque is given to the preliminarily selected speed change gear
pair linked to the clutch, and the play in the rotating direction
between the free gear and the slide gear in the speed change gear
pair can be reduced moderately. Consequently, it is possible to
reduce the collision sound generated between the free gear and the
slide gear due to the play, at the time of the subsequent
changeover of gear position.
Incidentally, the present invention is not limited to the above
embodiment. For example, each of the clutches 51a, 51b may be a
clutch which gets an engaging force or an operating force from a
spring, a motor, a solenoid or the like, and may be a dry type
clutch or a single disk clutch.
In addition, the engine 13 may be a single-cylinder engine, a
V-type engine, a horizontal opposed type engine, or the like, and
may be a longitudinal type engine having a crankshaft laid along
the vehicle front-rear direction, or the like.
Further, the transmission 47 may be one in which a slide member
separate from gears is slid to thereby change over the gear
position, and the number of speeds may be less than six or not less
than seven.
Moreover, the vehicle is not limited to a motorcycle, and may be a
saddle ride type vehicle with three or four wheels. Or, the present
invention may be applied to a motor scooter type vehicle having a
low-floor foot rest part.
In addition, the configurations in the above embodiment constitute
merely an example of the present invention. Naturally, the present
invention is applicable to four-wheel passenger cars and the like,
and various modifications are possible within the scope of the gist
of the invention.
The invention being thus described, it will be obvious that the
same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be obvious to one skilled in
the art are intended to be included within the scope of the
following claims.
* * * * *
References